<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .tou{
            width: 50px;
            height: 50px;
            border: 50px solid blue;
            box-sizing: content-box;
            
        }
        .chuan{
            width: 50px;
            height: 50px;
            border: 50px solid black;
            box-sizing: content-box;
            /* pointer-events: none; */
            position: absolute;
            left: 0;
            top: 0;
            z-index: 99;
        }
        .con{

        }
    </style>
</head>
<body>
    <div class="con"  onmouseenter="alert('11')">
        <div class="chuan"></div>
        <div class="tou" onmouseenter="alert('1133')">
            123456
        </div>
    </div>
    
</body>
</html>